透明热封聚丙烯中乙烯含量标准物质定值不确定度的评定

以乙丙丁三元共聚聚丙烯为乙烯含量标准物质定值样品,对乙烯含量测量不确定度的来源进行了分析和评定。结果表明,影响乙丙丁三元共聚聚丙烯乙烯含量标准物质不确定度的因素主要有样品均匀性、样品稳定性和各实验室定值结果的重复性。经过评定,乙丙丁三元共聚聚丙烯乙烯含量标准物质测定的不确定度为0.06,标称值为2.62±0.06。     

近红外漫反射分析技术在测定共聚聚丙烯中乙烯含量的应用

文章探讨了利用近红外漫反射分析技术快速判断共聚聚丙烯中的乙烯含量的应用。用近红外漫反射法收集了样品近红外光谱图。利用中红外方法测定共聚聚丙烯样品的乙烯含量。利用偏最小二乘法线性回归法建立了聚丙烯中聚乙烯含量的近红外光谱预测模型。将近红外法测定结果与中红外方法测定结果进行了比较,对光谱测量的重复性进行了考察。结果表明,利用近红外光谱法与中红外方法的测定结果无显著差异,近红外法具有准确,快速,操作简便和低成本等特点。     

无规共聚聚丙烯的透明化研究

研究了无规共聚聚丙烯中乙烯含量、成核剂、复合抗氧剂、除酸剂对无规共聚聚丙烯的透光率、雾度等透明性能的影响,制备的透明无规共聚聚丙烯的雾度为7％,透光率为93％,弯曲模量为1 100MPa.     

抗冲共聚聚丙烯在Novolen装置上的生产

对Novolen工艺中抗冲共聚聚丙烯生产的共聚反应机理、产品质量控制原理、工艺调节措施进行了综述。影响抗冲共聚物产品质量的主要因素有均聚物MFR、粉料总MFR、乙烯总含量和橡胶相中乙烯含量。只有对每个影响因素进行仔细选择和控制才能得到高质量的抗冲共聚聚丙烯产品。此外,以抗冲共聚聚丙烯2500H生产为例,对抗冲共聚聚丙烯产品的生产过渡步骤进行了研究,并对得到的产品进行了分析讨论。     

红外光谱法定性和定量分析聚烯烃中微量抗氧剂168

研究了用红外光谱法快速测定（聚乙烯、聚丙烯）中微量亚磷酸酯类抗氧剂168的含量，确定了其与固体粉料的混合方式为溶剂混合；分析了抗氧剂168与PE、PP粉料共混的FTIR图，确定了抗氧剂168在PE、PP中的特征吸收峰分别为854cm^-1、1082cm^-1，详细分析了抗氧剂168分别与特定组成的PE、PP、主抗氧剂1010及硬脂酸钙所制样品对所测谱图和所制曲线的影响。根据抗氧剂168的标准曲线可知。抗氧剂168的含量与其特征峰的吸收强度呈良好的线性关系，相关系数达0．96以上，样品中抗氧荆168的回收率高于94．7％。该方法已用于快速定性和定量分析实际样品。     

聚丙烯粉料的分子质量及其分布测定方法

采用凝胶渗透色谱(GPC)测定聚丙烯粉料加入不同类型、不同浓度抗氧剂后相对分子质量及其分布,结果表明,未加入抗氧剂的聚丙烯粉料相对分子质量随着时间的增加不断降低,而加入抗氧剂的聚丙烯粉料能保持稳定,浓度为50mg/Kg的抗氧剂1010可以达到很好的防降解效果。建立GPC测定聚丙烯粉料的分子质量及其分布的方法,该方法适用于生产过程中的中控检测。     

ICP-OES法测定PPR管材料中的金属含量

介绍了应用电感耦合等离子体发射光谱仪(ICP-OES)测定无规共聚聚丙烯(PPR)管材树脂粉料中金属含量的方法,包括样品的预处理、元素最佳分析线的确定、样品中元素的测定等。考察了共存元素、酸度对测试结果的影响,对方法的准确度、检出限、精密度进行了分析,结果表明本方法能够准确、快速地测定PPR生产过程产品中金属元素的含量。     

乙烯含量对透明无规共聚聚丙烯性能的影响

对国内市场已普遍认可的6种透明无规共聚聚丙烯的乙烯含量进行测试,确定了适合透明无规共聚聚丙烯的最佳乙烯含量。选择乙烯含量不同的无规共聚聚丙烯,考察乙烯含量对无规共聚聚丙烯力学性能、光学性能、溶出物含量的影响。结果表明:随着乙烯含量的增加,无规共聚聚丙烯的分子结构混乱度增加,熔融焓、透明性、韧性提高,熔点降低。同时,无规共聚聚丙烯中的二甲苯可溶物、正己烷提取物含量提高。     

波长色散型X荧光仪对PE中抗氧剂168含量的检测

使用波长色散型X射线荧光光谱仪,对聚乙烯中抗氧剂168含量进行测定与分析,提取抗氧剂168含量的方法需要使用聚乙烯反应器粉料,根据试验需要提取出不同含量的抗氧剂168,在乙醚溶剂中与聚乙烯粉料均匀混合后,使用熔融压片法制得标准样品,并使用波长色散型X射线荧光光谱仪和专用软件绘制出标准的曲线图,通过标准曲线图对样品进行测量,可以得到聚乙烯中抗氧剂168的具体含量。聚乙烯熔融压片制作样品的方法可以从样品制备、绘制曲线、参数优化以及测定结果等方面得到具体数据,得出后使用波长色散型X射线荧光光谱仪对聚乙烯中抗氧剂168含量进行测定。取代液相色谱测量法和紫外可见分光光度测量法等方法,使用该方法测定的数据准确,具有较好的精密效果,能够得到应用和发展。     

CPP薄膜专用三元共聚聚丙烯的结构与性能

分析了流延聚丙烯薄膜专用二元无规共聚聚丙烯W0723F与3种三元无规共聚聚丙烯的基本热力学性能、凝聚态结构、相对分子质量及其分布、结晶性能及流变性能。结果表明:二元无规共聚聚丙烯弯曲模量高,熔点高;3种三元无规共聚聚丙烯中1-丁烯含量相差不大,摩尔分数为5.1%~5.4%,乙烯含量相差较为明显,摩尔分数为3.0%~9.0%;两种进口产品的分子链序列结构中包含乙烯共聚链段,熔点低、熔融峰宽、晶体粒径小,产品具有较低的起始热封温度;流变性能分析表明,国产产品的加工流动性较好。     

SiC_p/B_4C复合陶瓷的热压烧结及组织性能

以Si粉为烧结助剂,SiC颗粒为增强剂,采用真空热压烧结工艺制备了SiCp/B4C陶瓷基复合材料。研究了SiCp对复合材料力学性能的影响。借助X射线衍射、扫描电镜等分析了复合材料的物相组成和微观结构。研究表明:添加的SiCp中粒径小的颗粒被包裹在主晶相中,粒径较大的颗粒分布在晶界上,形成"晶内-晶间"混合型复合陶瓷。当SiCp含量为4wt.%时,复合材料的弯曲强度和断裂韧性分别达到431MPa和5.41MPa.m1/2。复合材料力学性能的提高主要是由于残余应力引起的晶界强化以及断裂方式的转变。     

木粉/PP复合材料制备

用热压成型的方法制备了不同木粉含量的木粉／聚丙烯(PP)复合材料。结果表明，木粉含量高达90份时仍可热压成型，但以50份以下为优。通过采取加入添加剂、复合体粉料冷一机械共混与热一机械共混及挤出机挤出造粒、最终热压成型等工艺．可获得成形良好的木粉／PP复合材料。     

粉体热压法制备As2Se3硫系玻璃研究

本研究尝试将As₂Se₃红外硫系透镜生产过程中产生的块体玻璃废料进行回收利用,首先将清洗后的块体玻璃废料球磨成粉体,然后采用粉体热压技术实现高光学质量As₂Se₃玻璃片的制备。研究了粉体粒度、热压参数对制备的As₂Se₃玻璃光学性能的影响,对比了粉体热压法和熔融淬冷法制备的As₂Se₃玻璃的性能,评估了通过粉体热压途径制备红外硫系玻璃的可行性。结果表明:随着球磨时间的延长,As₂Se₃玻璃粉体的平均颗粒尺寸逐渐减小,且颗粒尺寸的分布趋于更加均匀;使用平均颗粒尺寸为9.7 μm的粉体(球磨10 min),在压力为40 MPa、热压温度为250 ℃、热压时间为10 min的条件下获得的热压玻璃的致密度达到99.8%,其折射率与熔融淬冷法制备的玻璃的折射率接近(在10 μm波长的折射率差仅为0.003),在10 μm波长的透过率达61%(理论透过率为63.7%)。通过进一步提高玻璃粉体的纯度和尺寸均匀性,有望制备出与熔融淬冷法制备的玻璃性能相当的热压玻璃。     

乙烯⁃醋酸乙烯共聚物纳米纤维网状结构黏合材料

通过添加无机盐改善乙烯?醋酸乙烯共聚物(EVA）纳米纤维静电纺丝困难的问题，得到一种网状结构的黏合材料。将其置于两层丙纶熔喷布之间，经热压得到复合材料。探究最佳纺丝参数及热压温度对层间剪切强度的影响，在最适温度下制备复合材料，并测试了其拉伸性能以及空气过滤效率。结果表明，当纺丝液浓度为6 %、三氯甲烷(CHCl₃)与四氢呋喃(THF)的质量比为7∶3，氯化锂(LiCl)添加量为0.2 %（质量分数，下同）时，EVA纳米纤维形态良好；80 ℃下热压时剪切强度最高；经测量复合材料的空气过滤效率能达到98.71 %以上，显著优于4层商用口罩熔喷布的过滤效率；复合材料的与力学性能复合前的熔喷布相比，也有了明显的提高。     

Fabrication of WC-Co cemented carbides with gradient distribution of WC grain size and Co composition by lamination pressing and microwave sintering

WC-Co composite powders with different particle sizes and Co contents were prepared by ball milling WC and Co powder mixtures for different durations. Functionally graded WC-Co cemented carbides with both Co content and WC grain size gradient were prepared by lamination pressing different WC-xCo (x?=?10, 15, 20) powder mixtures and microwave sintering the layered compacts. The WC-xCo powder mixtures were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), and the phase composition and microstructure of the functionally graded cemented carbides (FGCCs) were investigated by XRD, and FE-SEM coupled with energy dispersive spectroscopy (EDS). Mechanical behaviors of the layered WC-Co materials were measured and compared with those of WC-Co cemented carbides with single composition. The results showed that increasing the milling time from 6 to 24?h, results in the decrease of the particle size of WC-Co composite powders from 0.31 to 0.11?µm. After lamination pressing and microwave sintering, the WC-Co samples show nearly complete densification with a relative density higher than 99.7% and no ?-phase was detected in the FGCCs. The Co content and WC grain size in FGCCs decrease from the core to the surface. Homogenization of Co has hardly occurred and no cracks have formed between the layers in the sintered samples. In the inner layer, the mean WC grain size is 529?nm, while in the outer layer it is only 274?nm. Because of the difference in Co content and WC grain size, FGCCs have a Rockwell hardness of 90.75 HRA at the surface, which decreases to 86.75 HRA in the core. However the fracture toughness increases from 11.53 at the surface to 18.12?MPa?m^?1/2 in the core. The present results show that FGCCs with high outer layer hardness and high inner layer toughness were successfully prepared.     

Preparation of fully dense and magnetically controllable CaO-Al2O3-SiO2-Na2O-Fe3O4 glass ceramics by hot pressing

Fully dense and magnetically controllable glass ceramics was successfully synthesized by method of hot pressing using CaO-Al₂O₃-SiO₂-Na₂O glass powder and Fe₃O₄ powder as raw materials. The influences of sintering temperature and time, content and particle size of Fe₃O₄, as well as particle size of glass powder on the densification and magnetic properties of samples were investigated. It was found that the saturation magnetization gradually increased with increasing magnetite content. In addition, the samples containing smaller size magnetite particles had a higher coercivity. However, for samples using smaller size glass powder, magnetite particles could partially dissolve into the glass matrix, which led to the decrease of saturation magnetization and the increase of coercivity. It was also concluded that the precipitation of crystalline phase from smaller size glass powder caused the decrease of degree of densification, and after decreasing the sintering temperature, the degree of densification of product was enhanced.     

Si3N4—SiC复相陶瓷增强颗粒尺寸效应

本文采用不同颗料尺寸的SiC粉体与Si3N4复合，采有热压烧结工艺制备了Si3N4-SiC复相陶瓷材料。研究了不同SiC颗粒尺寸、含量对复合材料致密化、显微结构和力学性能的影响。结果表明，晶粒尺寸越小强度越高，硬度也越大，但断裂韧性随粒径的变化不大。验证了颗粒复合的均匀分布模型和增强分布模型。     

激光衍射法测定细微滑石粉粒度的研究

文章研究了分别以焦磷酸钠、六偏磷酸钠、乙醇、乙二醇单丁醚作为分散剂时使用激光粒度仪对细微滑石粉粒度的测定情况,确定了使用乙醇:乙二醇单丁醚=2:1的混合溶剂进行预分散,再加入水中使用激光粒度仪测定粒度的最佳方法。使用该方法测得的细微滑石粉粒度(D90)RSD为0.49%。     

Experimental study of oil particle emission rate and size distribution during milling

Metalworking fluids (MWFs) used in milling generate oil particles through impaction, action of centrifugal forces and evaporation/condensation mechanisms. The oil particles suspended in the factory atmosphere can affect the health of the labor force. In order to study the emission properties of these oil particles, this work investigates the oil particle emission rate and size distribution during milling using an environmental chamber method. Two commonly used operating modes for MWFs were selected, the minimum quantity lubrication (MQL) mode (40?ml/h) and the cooling mode (1 m³/h). The cooling mode without cutting was studied separately for comparison with the cooling mode with cutting. The results show that the oil particle emission rate in milling ranges from 7.2 to 641?mg/h, and the size distribution ranges from 0.265 to 12.5?µm. Evaporation/condensation is the main mechanism in the MQL mode. The majority of oil particles formed by evaporation/condensation are in the range of 0.265 to 1.8?µm. As the tool rotation speed increases, the particle emission rate increases, while the mass mean diameter (MMD) and the sauter mean diameter (SMD) decrease. Oil particles are mainly generated by the action of centrifugal force in the cooling mode, and mainly distributed in the range of 1.8 to 12.5?µm. The particle emission rate increases with the tool rotation speed, and the particle MMD and SMD increase with the tool rotation speed only in the cooling mode without cutting. The particle emission rate ranging from 1.8 to 12.5?µm, as well as PM5 and PM10, are a polynomial function of the square of tool rotation speed during the cooling mode. The coefficient of determination (R²) is above 0.99.

© 2018 American Association for Aerosol Research     

二元醇对分散荧光染料墨水性能的研究

采用纳米粒径分析仪对分散荧光染料色浆的主体颗粒大小进行了研究,分析了二元醇对墨水的黏度、表面张力、保湿性、热储存稳定性、离心稳定性、墨水转移率以及喷墨转移印花后涤纶织物荧光反射率的影响。实验结果表明,采用湿磨法研磨后的染料色浆分散稳定性好,粒径为125.5 nm。二元醇质量分数低于15%时,墨水黏度变化不大;当其质量分数超过15%后,墨水黏度的增幅明显。由于氢键作用力的存在,墨水的保湿性随二元醇质量分数的增加不断提高,其中乙二醇的保湿效果最好。添加15%(质量分数)二元醇的墨水具有较好的热储存稳定性和离心稳定性。二元醇用量的增加有利于墨水转移率和涤纶织物荧光反射率的提高;但其用量过多,也会使转移率和荧光反射率降低。